I agree with you. Most places allow you to trim limbs coming from a neighbors tree that are interfering with your property. That does NOT however mean you have a right to trim the tree even with the property line. Besides, like someone else said, who would want to except to start an argument?? A healthy tree growing on your neighbors property can be as much an asset to your home as one growing on your property.
A person who would trim a tree even with the lot line would probably object to the shade a neighbor's item cast upon his property. This could be only the beginning of a feud!